1. Field of the Invention
This invention relates to an improved extendible beam or column system, and in particular to an extendible mast for supporting an antenna, and also to an improved method of erecting same.
The invention-will have many applications, such as antenna support masts, ladders, booms or any other elongate rigid column member used as a support structure. However, the invention will be described in relation to antenna support masts, realising that the scope of the invention is not to restricted to this application.
2. Background Information
Antenna support masts or towers comprising a plurality of telescopic sections telescoped one within the other, and which are normally operated by means of a hand pump are well known and in common use for antenna systems required for field use, e.g. by army personnel. Such mast systems suffer from a number of disadvantages. They are relatively expensive and not very reliable in use due to the tendency of the telescoping sections to "stick" on the seals when raising or lowering them by means of the pump. This can slow down quite significantly both the erection and the pull-down time which in some situations, e.g. military operations, may be quite critical. Furthermore, the cables leading to the antenna are required to be carried externally of the tubular telescoping sections and hence are prone to damage both during use of the antenna and transportation thereof. A still further disadvantage is their relatively heavy weight which renders their handling more difficult.
It is the main object of the present invention to provide an improved extendible column or mast for supporting an antenna, especially for those used in the field, which obviates at least some of the aforementioned disadvantages, and in particular one which is able to be very quickly erected and pulled down, and which is able to be easily repaired in the field.
It is a further object of the present invention to provide an extendible mast which can be constructed so that it is less likely to fail during operation in adverse environmental conditions, e.g. heat, salt spray and dust in comparison to known mast systems of a similar type.